STUDIES ON IN-VIVO ENDOTOXIN PLASMA DISAPPEARANCE TIMES IN CATTLE

Endotoxin plasma disappearance (EPDT) times were determined by a modif ied Limulus amoebocyte lysate (LAL) assay technique after the intraven ous administration of 25 mu g E. coli O55:B5 endotoxin per kg b.w. to 22 Jersey cows. Clinically healthy cows (n = 6) cleared endotoxin from the plasma within 30 min. Cows pretreated with flunixin meglumine (n = 6) had 2-3 times longer plasma disappearance times, while cows pretr eated with phenylbutazone (n = 6) had plasma disappearance times which were 6-12 times longer than the healthy control group. A fourth group comprised clinical cases of spontaneously developed hepatic lipidosis (n = 4). None of these cows were able to clear the injected endotoxin dose and one died before the end of the experiment. The acute phase r esponse, described by leukocyte and thrombocyte counts and plasma gluc ose and zinc concentrations, was not statistically different between t he four groups.